【作者】 李华丽；

【导师】 何煜波；

【作者基本信息】 湖南农业大学 ， 食品科学， 2005， 硕士

【摘要】 本研究以传统湘西酸肉为基础，结合现代发酵工艺，从主发酵工艺条件、不同发酵方式对后发酵的影响、Nisin和壳聚糖对后发酵的影响以及辅料的选择这4个方面对酸肉的现代化生产工艺进行了研究。通过对酸肉主发酵期一定产酸速度及后发酵品质保障的探索，找到了符合现代化工业及现代消费要求的生产途径，为实现传统酸肉制品的产业升级铺垫了道路。本研究表明：1通过单因素试验和正交试验确定酸肉主发酵期的盐浓度、葡萄糖浓度、接种量、发酵时间和发酵温度这5个影响因素，结果表明最佳工艺条件为盐0％或1％，葡萄糖1％，接种量8％(米酒乳杆菌：戊糖片球菌=3：1)，发酵时间18h，发酵温度34℃。2采用4种不同接种方式对酸肉进行发酵研究，即辅料接种原料肉不接种、原料肉接种辅料不接种、原料肉与辅料混合接种和自然发酵这4种接种方式。结果表明原料肉和辅料混合接种发酵的产品产酸速度最快，但在后发酵期间酸味过于刺激；自然发酵酸肉缓慢产酸，酸味柔和，但其用盐量(4％)偏高。不同接种方式对AN的生成没有显著差异，均需一定的后发酵时间才能形成良好的风味。3采用盐、Nisin和壳聚糖对酸肉后发酵进行单因素试验，结果表明单独使用其中任何一种抑菌因子其效果不理想。经正交试验确定复合因子的优水平为盐2％，Nisin 0.08％，壳聚糖2％；其产品在25℃进行后发酵20d后，其pH值为4.48、TVB-N值为13.8mg／100g、TBA值为0.35mg／100g、AN为136.2mg/100g、细菌总数为6.7×10~5、大肠菌群＜30个／100g、感观评分为85。4用玉米粉、粟米、糯米粉和籼米粉为辅料与原料肉发酵对产品的生化指标和感官评价有一定影响，其淀粉和蛋白质含量是影响的主要因素，表现为pH值降低幅度和总酸含量随原料淀粉含量而增大，AN值随原料蛋白质含量而增大。研究结果表明，糯米粉是酸肉生产的首选辅料。5通过对肉品发酵前后游离氨基酸变化的测定，可看出酸肉游离氨基酸总量有显著变化，发酵30d时的酸肉游离氨基酸含量是发酵前的约1.58倍。除胱氨酸的含量有所下降外，其它氨基酸的含量均有不同程度的增加。其中谷氨酸、苏氨酸、精氨酸、缬氨酸和组氨酸的含量增加2-5倍。大大提高了产品的营养价值。6确定了人工接种纯乳酸菌生产湘西酸肉的工艺路线为：原料肉→切片→拌糯米粉→加1％葡萄糖→接种(8％，Ls：Pp=3：1)→主发酵(34℃，18h)→加2％盐，0.08％Nisin，2％壳聚糖→后发酵(25℃，20d)→包装→成品更多还原

【Abstract】 On the bases of traditional production process this paper studied modernfermentation technology of Xiangxi Nanx Wudl at four aspects, including formerfermentation process, influence of different inoculating methods on later fermentation,influence of Nisin and Chitosan on later fermentation, and choosing of thesupplementary materials. The process in correspondence of modern production andconsuming requirement was determined through studying the acidity rate duringformer fermentation and the quality during later fermentation. So it was useful fortraditional Nanx Wudl to be industrialized. The conclusions were as follows:1 Five influential factors during former fermentation of Nanx Wudl weredetermined by single-factor and orthorgonal experiments, which were concentrationof salt and glucose, inoculating amount, time and temperature of fermentation. Theresults showed that the best process conditions were 0% or 1% of salt concentration,1% of glucose concentration, 8% of inoculating amount (Lactobacillus sake:Pediococcoi pentosaceus=3:1), 18h of time fermentation, and 34℃of temperaturefermentation.2 Comparison of different inoculating methods of Nanx Wudl were studied,which were: (1) inoculating supplementary material only,(2) inoculating raw meatonly,(3) inoculating both raw meat and supplementary material (4)naturalfermentation. The results showed that the method of inoculating both raw meat andsupplementary material had some benefits to acidity rate, yet sensory evaluationshowed the product was a little over acid during later fermentation. The acidity rate oftraditional product was slow and the acid flavor of it was soft. There was no obviousdifference on AN among different inoculating methods, and later fermentation timewas needed for better flavor. 3 Single-factor experiments about effects of salt, Nisin and Chitosan on laterfermentation showed that there were no much benefits by using any sort ofpreservative. Orthorgonal experiment showed that the best levels of the multiplepreservative were conformed as: 2% of salt concentration, 0.08% of Nisin and 2% ofChitosan. Under the best later fermentation condition, the product had thecharacteristics as follows: 4.48 of pH, 13.8mg/100g of TVB-N, 0.35mg/100g of TBA,136.2mg/100g of AN, 6.7×10~5 cfu/g of bacteria amount, colifrom＜30/100g, andsensory evaluation value of 85.4 Corn powder, maize, glutinous rice powder and nonglutinous rice powder hadeffects on biochemical characteristics and sensory evaluation of the product. Theirstarch and protein content were the main influent factors. It showed that the morecontent of starch and protein, the more total acidity and reducing rate of pH value.Also the more content of protein, the more AN value. Sensory evaluation manifestedthat glutinous rice powder was most suitable among those supplementary materials.5 There were obvious changes of free-amino acid between raw meat and fermentedproduct. Free-amino acid content of Nanx Wudl aider fermented for 30d was about1.58 times that of raw meat. Except for the reduction of Cys content, the contents ofthe other free-amino acid increased in different degree. And the contents of Glu, Thr,Arg, Val and His were increased by 2-5 times. It meant that the nutrient value ofproducts was greatly enhanced.6 The production technolory of Xiangxi Nanx Wudl inoculated with Lactic acidbacteria was that: raw meat→slicing→mixed with glutinous rice powder→addedwith glucose(1%)→added with starter culture (8%, Ls: Pp=3:1)→formerfermentation (34℃, 18h)→added with salt(2%), Nisin(0.08%) and Chitosan(2%)→later fermentation (25℃, 20d)→packaging→product更多还原